Electric lighting arrangement



A ril 26, 1966 F. KNUPPEL ELECTRIC LIGHTING ARRANGEMENT 5 Sheets-Shee 1Filed Oct. 10, 1962 Fig.4

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. INV ENTOR FR M KMUWEL HbENTS the central contact.

United States Patent 3,248,685 ELECTRIC LIGHTING ARRANGEMENT FritzKnuppel, Westphalia, Germany, assignor to Vossloh- Werke G.m.b.H.,Westphalia, Germany Filed Oct. 10, 1962, Ser. No. 229,690 Claimspriority, applicafizoln Germany, Oct. 12, 1961,

,453 15 Claims. (Cl. 339178) This invention relates to electric lightingarrangements, and more particularly to a lamp socket and to acorresponding lamp base which are threadedly engageable for transmissionof current from the socket to the base in the threadedly engagedoperative position of socket and base.

The invention is more particularly concerned with a safety arrangementfor preventing accidental touching of the current transmitting contactsof the lamp base and of the socket. In a known socket type a centralcontact of the socket is arranged in an axial recess of an insulatingcontact carrier, and the lamp base is provided with correspondingaxially projecting contact mean-s received in the recess of the socketin the operative position of the arrangement for abutting engagementwith While the known socket makes it difficult, or almost impossibleaccidentally to touch the central contact, the second contact on thelamp base and on the socket is still substantially exposed unless aninsulating sleeve or a similar protecting member is provided to enclosethe second contact. When a substantial measure of protection againstaccidental touching of exposed contacts is necessary, the conventionallamp and socket arrangements require relatively complex and expensiveprotective insulating sleeves or the like.

The primary object of the invention is the provision of a lightingarrangement of the type described which is simpler than the knownarrangement.

A more specific object is the elimination of the need for a protectiveinsulating sleeve.

Another object is the provision of threadedly engageable lamp bases andlamp sockets in which the engaged threaded portions are electricallyinsulated from all current carrying members of the lamp and of thesocket.

Other objects and manyof the attendant advantages of this invention willbe readily appreciated as the same becomes better understood byreference to the following detailed description when considered inconnection with the accompanying drawings in which like referencenumerals designate like parts throughout the figures thereof andwherein:

FIG. 1 is an axially sectional fragmentary view of the base of anincandescent lamp;

FIGS. 2, 3, and 4 illustrate modifications of the lamp base of FIG. 1 incorresponding views;

FIG. 5 shows the contact carrier arrangement of a lamp socket adapted toengage the lamp bases shown in FIGS. 1 and 3, the carrier arrangementbeing shownin axial section;

FIG. 6 is a top view of the contact carrier arrangement of FIG. 5;

FIG. 7 shows the same contact carrier arrangement in a bottom view;

FIG. 8 is an axially sectional view of a lamp base of the inventionsimilar to those shown in FIGS. 2 and and engaged in a conventionalEdison type screw socket, the lamp base and socket being shown insection on the common axis;

FIG. 9 illustrates a modification of the l-amp'base shown in FIG. 4engaged in a conforming socket, the view being in axial section;

FIG. 10'illustrates in axial section a modification of the lamp baseshown in FIG. 3 engaged in a socket in- 3,248,685 Patented Apr. 26, 1966cluding a metallic shell and the contact carrier arrangement of FIGS. 5to 7;

FIG. 11 shows the arrangement of a lamp and socket similar to the deviceillustrated in FIG. 10, but including a socket provided with aninsulating shell.

Referring first to FIG. 1, there is seen a portion of an electricincandescent lamp including a base member 1 of thermosettingnon-conductive plastic material to which a glass bulb is fastened in aconventional, non-illustrated manner. member 1 is shown, it beingunderstood that the base member is substantially symmetrical withrespect to its axis 41. For more convenient description, the base end ofthe lamp will be referred to hereinafter as the lower end of the lamp,and other spatial relationships will be described accordingly, it beingunderstood that such terms as top or bottom do not necessarily indicatea fixed orientation relative to the field of terrestrial gravity.

The base member 1 has coarse external threads 42 centered on the axis 41and conforming to the standards for Edison type screw sockets. Ametallic central contact pin 2 projects axially from the bottom face ofthe base member 1. The pin 2 is tubular and receives the end of a lead 3in its axial cavity. The lead is conduc' tively connected to the pin 2by a drop of solder 43 as is conventional. The lead 3 is integral withor otherwise conductively connected to the filament of the lamp, notshown in its entirety. The other filament lead 4 passes through a bore44 in the base member 1 and is attached by a solder joint 45 to acylindrical outer contact band 5 of metallic material coaxial with thepin 2 and radially spaced therefrom. The band 5 is fastened to the basemember 1. The pin 2 and the band 5 thus constitute the terminals oftheinternal lamp circuit which also includes the filament.

The modified lamp base shown in FIG. 2 differs from that illustrated inFIG. 1 mainly by the configuration of its outer contact member 6 whichhas an annular conical portion 46 and a flat annular portion 47. The twoportions 46, 47 are integral and conform to the surface of the basemember 1. The contact member 6 is attached to the base member 1' 'by anintegral beaded edge 48 of the conical portion 46 which engages acorresponding recess in the base member 1.

The base member 8 of the lamp base seen in FIG. 3 isaxially shorter thanthe base member 1. A coaxial metal shell 7 is attached to the basemember 8 and is formed into the shape of helical threads substantiallyidentical with the threads 42. In all other respects, the lamp baseillustrated in FIG. 3 is so closely similar to that shown in FIG. 1 asto make further description unnecessary.

FIG. 4 differs from FIG. 2 as FIG. 3 differs from FIG. 1. In FIG. 4, anaxially shortened base member 8' carrying a threaded metallic shell 7replaces the base member 1' and its integral threads shown in FIG. 2.

A contact carrier arrangement for a socket engageable with the lampbases shown in FIGS. 1 and 3 is illustrated in FIGS. 5 to 7 in axialsection, in top view, and in bottom view respectively. There is seen acontact carrier member 9 having the general shape of a circular disc,and made of ceramic insulating material. An axial passage or recess 10in the carrier member 9 has a diameter only slightly larger than that ofthe pin 2 which is shown in phantom View in FIG. 5 together with otherelements of the lamp bases of FIGS. 1 or 3. A screw terminal 11 recessedin the underside of the carrier member 9 holds a resilient contact blade12 over the lower orifice of the passage 10 for abutting engagement withthe pin 2.

An annular groove 13 in the top face of the carrier Only one half of thelower end of the base arrangement. A second screw terminal 15 mounted ina recess at the underside of the carrier member 9 serves as fasteningmeans for a spring blade 16 which is stirrupshaped as best seen fromFIG. 7, and whose free ends project from beneath through openings 14into the groove 13 for abutting contact with the band 5. When the lampbase shown in FIGS. 1 or 3 is inserted into a socket equipped with thecontact carrier arrangement illustrated in FIGS. to 7, the contactblades are resiliently displaced from the positions shown in FIG. 5 infully drawn lines to the positions indicated by broken lines.

The lamp base and contact carrier member are held in their operativeposition by threaded engagement between the lamp base and an outer shellwhich envelops the contact carrier member as will become apparenthereinafter.

Referring next to FIG. 9, there is shown a lighting arrangementconsisting of a socket and a lamp of which only the base is visible. Thelamp base is similar to that illustrated. in FIG. 2, and differs fromthe latter by a base member 58 which has a central frusto-conical recess24 coaxial with the pin 2. A conforming frusto-conical projection 23 onthe top face of the cooperating contact carrier member 59 engages therecess 24. A central axial passage 22 receives the pin 2 in theoperative position illustrated for contact with a blade 12 fastened tothe contact carrier member 59 by a coordinated screw terminal in themanner evident from FIG. 5, but not shown in FIG. 9 in order not tocrowd the drawing. A second contact blade 25 eccentrically arranged onthe carrier member 59 makes contact with an annular contact member 6 onthe lamp base.

The contact member 59 and the elements supported thereon are envelopedin an outer sheet metal shell having a cup-shaped lower portion 30 andan upper portion 27 of basically cylindrical stepped shape. Aninternally threaded connector 60 fixedly fastened to the bottom part ofthe lower shell portion 30 permits the socket to be attached to atubular lamp support or the like. The approximately cylindrical top partof the lower shell portion 36 is threadedly inserted into a conformingcylindrical bottom part of the upper shell portion 27. The engagedthreads on the two shell portions are axially coextensive. The top part26 of the upper shell portion 27 has a smaller diameter than the bottomportion and is formed into threads coaxial with the engaged threads ofthe two shell portions, but axially spaced from the same. The top part26 threadedly receives the metallic threaded shell 7 of the lamp base,whereby the central pin 2 and the outer contact 6 are held in engagementwith the corresponding contact elements 12, 25 of the socket.

The lower portion 30 of the socket shell has an inwardly projectingintegral loop 61 which radially engages a slot 62 in the contact carriermember 59. The upper shell portion 27 carries an internally threadedmember 63 in which a screw 28 is axially movable. The head of the screwprojects outward of the shell, and its pointed free end engagescorrugations 29 on an annular rim of the contact carrier member 59. Theloop 61 permanently prevents rotation of the lower shell portionrelative to the contact carrier member, and the screw 28 may be rotatedby means of a screw driver to lock the upper shell portion againstrotation relative to the contact carrier member, thereby preventingaccidental opening of the threaded-connection between the shellportions.

A short nipple 64 is secured in the lower shell portion 30 in such amanner as to permit insertion of a nonillustrated grounding wire fromthe outside. A set screw 65 is transversely threadedly movable on thenipple 64, and conductively fastens the grounding wire to the outersocket shell.

The embodiment of the invention shown in FIG. combines the lamp base ofFIG. 1 with the contact carrier arrangement of FIGS. 5 to 7 with thecooperation of an outer metallic shell consisting of a cup-shaped lowerportion 30 and an upper portion 27' of stepped cylindrical shape. Thetop part 17 of the upper shell portion 27' provides a threaded supportfor the lamp whose base member 1 is threadedly engaged in the top part17. A flange 31 on the bottom rim of the upper shell portion 27'supports a lamp shade 32 which is held against the flange 31 by anannular adapter 33 threadedly engaging the bottom part of the uppershell portion 27'. The several threads on the upper shell portion whilediffering in diameter have identical pitch so that they may besimultaneously formed in a single thread rolling operation.

The embodiments of the lighting arrangement of the invention illustratedin FIGS. 9 and 10 provide good protection against accidental contact ofa user with a current carrying part although the outer shell of thesocket consists of metal. The outer threads on the lamp base areinsulated from the current carrying elements of the lamp. The socketcontacts are arranged in such a manner that they cannot make contactwith a metallic shell on the lamp base. A transmission of electricpotential by the shell of the lamp base to the socket shell is thusrelably prevented when the socket of the invention is used with theconforming lamps.

When a conventional light bulb equipped with an Edison type screw baseand having one filament terminal connected to a screw shell and theother to a central button on the bottom of the lamp base is threadedlyinserted into a socket of the invention, the central contact buttoncannot reach the contact arranged in the central recess or passage inthe contact carrier member of the socket. The conventional shell cannotreach the recessed outer contact of the socket shown in FIG. 10, andcannot .be inserted deeply enough into the socket to reach the contactelement 25 in FIG. 9 because of abutting engagement of the contactbutton with the upper terminal face of the projection 23 while the lampbase shell is still spaced from the contact element 25.

Known light bulbs equipped with a current carrying screw shell and a pintype second contact can readily be excluded from use with the sockets ofthe invention by suitably dimensioning the central passage in thecontact carrier member. If the passage is made too narrow to accommodatethe pin of the known lamp, or too long to permit the contact blade 12 tobe reached, a lamp of the last mentioned known type will neither belighted when inserted in the socket of the invention, nor can ittransmit electric potential to a outside face of the socket.

Even when not equipped with an electric lamp, the sockets shown in FIGS.9 and 10 are not apt to transmit an accidental electric shock to a user.All external parts are safe as has been set forth above. A fingerinserted into the socket shown in FIG. 10 cannot reach current carryingparts. The conical projection 23 at the bottom of the socket illustratedin FIG. 9 makes it very unlikely that the contact element 25 may bereached accidentally by an inserted finger. It is of course possible toeliminate this danger by connecting the element 25 to that conductor ofthe current supply which is at ground potential or very close thereto.The screw terminal of the element 25 may be provided with indiciaindicating that it be connected to a grounded lead, or the element 25may be directly grounded through a wire attached to the nipple 64.

While conventional lamps cannot be employed with the sockets of theinvention, those lamps of the invention which are equipped with anupwardly flaring extension portion on their annular outer contactelement in the manner shown in FIGS. 2 and 4 may be employed in standardEdison type screw sockets. An example of a lamp base of the inventioninserted in such a conventional socket is shown in FIG. 8.

The lamp base of the invention shown in FIG. 8 combines features of thebases illustrated in FIGS. 3 and 4 and is normally intended for use witha socket having a contact carrier member of the type shown in FIGS. 5 to7. The lamp base has a central contact pin 2 and a cylindrical outercontact band 19 closely similar to the band 5 seen in FIG. 3. Asubstantially conical annular element 20 is integrally connected to thecontact band '19 and flares therefrom outward so that its outer rim isclose to a cylinder surface defined by theroots of the external threadson the lamp base. The rim thus also is in a position of contact with theusual threaded sleeve of the Edison type socket when the pin 2 abutsagainst the central button contact 38 inthe socket. The latter has beenshown only to the extent necessary for an understanding of itscooperation with the lamp base of the invention since it is well knownin itself. The outline 21 of a light bulb equipped with a conventionalEdison type screw base is indicated in chain dotted lines for comparisonpurposes.

An additional lighting arrangement of the invention is illustrated inFIG. 11 in which a structure substantially similar to that of FIG. 10 isequipped with an outer shell of molded insulating material such asplastic replacing the outer metal shell of the embodiments describedhereinbefore. The contact carrier member 9 and the contact elementssupported thereon are substantially identical with those shown in FIGS.5 to 7 and 10. The lamp mounted on the socket has a bulb 39 and a socketof the type shown in FIG. 1. The plastic socket shell has a lowerportion 34 threadedly engaging a substantially cylindrical upper portion35. The contact carrier member 9 is held within the shell between anintegral internal annular collar 36 on the upper portion 35 and ashoulder on the lower shell portion 34. A threaded metallic supportmember 18 is attached to the 'collar 36 by fasteners 37. I

Various modifications are contemplated and may obviously be resorted toby those skilled in the art Without departing from the spirit and scopeof the invention as hereinafterdefined by the appended claims, as onlyprefered embodiments thereof have been disclosed.

What- I claim is:

1. An electric lighting arrangement comprising, in combination:

(a) socket means including (1) a contact carrier member having a topface;

(2) an internally threaded support member secured to said carriermember, the threads of said support member having an axis transverse tosaid top face, said top face being formed with a recess extending alongsaid axis;

(3) a first contact member in said recess and axially spaced from saidtop face; and

(4) a second contact member on said carrier member and radially spacedfrom said axis; an

lamp base means including 1 (l) a base member of insulating material;

(2 external thread means on said base member and engageable with saidthreads of said support member in the operative position of saidarrangement, said external thread means having an axis coinciding withthe axis of said threads in said operative position;

(3) contact pin means axially projecting from said base member, said pinmeans being adapted to be received in said recess for abuttingengagement with said first contact member in said operative position;

(4) outer contact means on said base member spaced from said axis andopposite said contact carrier member for engagement with said secondcontact member in said operative position of the arrangement; and

(5) an internal circuit on said base member, said contact pin means andsaid outer contact means constituting the terminals of said circuit;

(6) portions of said base member being intersaid second contact memberand said outer contact means.

constitute a pair of outer contacts, one member of said pair beingsubstantially annular about said coinciding axes, and flaring in adirection away from the other member of the pair.

3. An arrangement as set forth in claim 1, wherein said contact carriermember is formed with an annular groove in said top face, said secondcontact member being arranged in said groove, and said outer contactmeans include a cylindrical sleeve member of conductive material coaxialwith said pin means and received in said groove in said operativeposition.

4. An arrangement as set forth in claim 3, wherein said outer contactmeans further include an annular extension portion integral with saidcylindrical sleeve member and flaring in a direction axially away fromsaid sleeve member and from said annular groove.

5. An arrangement as set forth in claim 1, wherein said external threadmeans are of electrically insulating material.

6. An arrangement as set forth in claim 1, wherein said external threadmeans define a coaxial cylinder surface, said second contact member hasa contact portion axially spaced from said thread means and from'theprojecting portion of said contact pin means, said contact portionextending in said cylinder surface.

7. An arrangement as set forth in claim 1, wherein said socket meansfurther includes a projection on said top face, said projection being ofsubstantially circular cross section coaxial with said threads andhaving an axially terminal face remote from said top face, said recessextending through said projection along the axis of said threads, andsaid base member being formed with a recess substantially conforming tosaid projection, said projection being received in the conforming recessin said operative position of the arrrangement, said second contactmember being axially spaced from said terminal face in a directiontoward said top face.

8. An arrangement as set forth in claim 7, wherein said projection issubstantially conical.

9. An arrangement as set forth in claim 1, wherein said socket meansfurther includes outer shell means integral with said threaded supportmember and substantially enveloping said cont-act carrier member andsaid contact members.

10.-An arrangement as set forth in claim 1, wherein said' socket meansfurther include outer shell means at least partly consisting ofelectrically insulating material, and substantially enveloping saidcontact carrier member and said contact members, said threaded supportmember essentially consisting of metallic material and being mounted onsaid shell means.

11. An arrangement as set forth in claim 1, wherein said support memberis of tubular sheet metal formed with said internal threads and withcorresponding axially coextensive external threads having the same pitchas said internal threads, said support member being formed withadditional threads axially spaced from said internal threads and havingsaid pitch.

, 12. An arrangement as set forth in claim 1, wherein said socket meansfurther include outer shell means enveloping said contact carrier memberand said contact members, said shell means including an upper portionand a lower portion threadedly engaged and threadedly movable relativeto each other about said transverse axis, and locking means movable onone of said portions and engageable with said contact carrier member forselectively locking said one portion against rotary movement relative tosaid contact carrier member about said transverse axis. 13. Anarrangement as set forth in claim 1, wherein said contact pin means hasa free end portion axially spaced from said base member, and said outercontact means is axially spaced from said free end portion in adirection toward said base member.

14. An arrangement as set forth in claim 1, wherein said outer contactmeans on said base member is axially spaced from the threads of saidsupport member in the operative position of said arrangement.

15. An arrangement as set forth in claim 14, wherein said lamp basemeans includes insulating means interposed between said outer contactmeans and said threads of the support member in said operative positionof said arrangement.

References Cited by the Examiner UNITED STATES PATENTS 287,314 10/1883Perkins 339-177X 320,030 6/1885 Weston 339--145 8 10/1894 H-ussey339-4146 X 5/1932 Vello 339-146 X 6/1935 Farish 339182 X 10/1936 Borell339177 X 4/1937 Okino 339-178 X 5/1939 Buser 339178 5/1958 Bauer et a1.33972 5/1963 Takes et al. 339-177 FOREIGN PATENTS 4/1953 Germany.12/1953 Germany. 6/1956 Germany.

11/ 1952 Switzerland.

15 JOSEPH D. SEERS, Primary Examiner.

ALBERT H. KAMPE, Examiner.

W. DONALD MILLER, Assistant Examiner.

1. AN ELECTRIC LIGHTING ARRANGEMENT COMPRISING, IN COMBINATION: (A)SOCKET MEANS INCLUDING (1) A CONTACT CARRIER MEMBER HAVING A TOP FACE;(2) AN INTERNALLY THREADED SUPPORT MEMBER SECURED TO SAID CARRIERMEMBER, THE THREADS OF SAID SUPPORT MEMBER HAVING AN AXIS TRANSVERSE TOSAID TOP FACE, SAID TOP FACE BEING FORMED WITH A RECESS EXTENDING ALONGSAID AXIS; (3) A FIRST CONTACT MEMBER IN SAID RECESS AND AXIALLY SPACEDFROM SAID TOP FACE; AND (4) A SECOND CONTACT MEMBER ON SAID CARRIERMEMBER AND RADIALLY SPACED FROM SAID AXIS; AND (B) LAMP BASE MEANSINCLUDING (1) A BASE MEMBER OF INSULATING MATERIAL; (2) EXTERNAL THREADMEANS ON SAID BASE MEMBER AND ENGAGEABLE WITH SAID THREADS OF SAIDSUPPORT MEMBER IN THE OPERATIVE POSITION OF SAID ARRANGEMENT, SAIDEXTERNAL THREAD MEANS HAVING AN AXIS COINCIDING WITH THE AXIS OF SAIDTHREADS IN SAID OPERATIVE POSITION; (3) CONTACT PIN MEANS AXIALLYPROJECTING FROM SAID BASE MEMBER, SAID PIN MEANS BEING ADAPTED TO BERECEIVED IN SAID RECESS FOR ABUTTING ENGAGEMENT WITH SAID FIRST CONTACTMEMBER IN SIAD OPERATIVE POSITION; (4) OUTER CONTACT MEANS ON SAID BASEMEMBER SPACED FROM SAID AXIS AND OPPOSITE SAID CONTACT CARRIER MEMBERFOR ENGAGEMENT WITH SAID SECOND CONTACT MEMBER IN SAID OPERATIVEPOSITION OF THE ARRANGEMENT; AND (5) AN INTERNAL CIRCUIT ON SAID BASEMEMBER, SAID CONTACT PIN MEANS AND SAID OUTER CONTACT MEANS CONSTITUTINGTHE TERMINALS OF SAID CIRCUIT; (6) PORTIONS OF SAID BASE MEMBER BEINGINTERPOSED BETWEEN SAID THREAD MEANS AND SAID CIRCUIT, AND CONSTITUTINGINSULATING MEANS ELECTRICALLY INSULATING SAID INTERNAL CIRCUIT FROM SAIDTHREAD MEANS.